Stylicletodes wellsi, Ma & Liu & Li & Huys, 2021

Ma, Lin, Liu, Qing He, Li, Xin Zheng & Huys, Rony, 2021, A new species of Stylicletodes Lang, 1936 (Copepoda: Harpacticoida: Cletodidae) from the East China Sea, including an updated key to species and synopsis of distribution records, Zootaxa 5051 (1), pp. 423-442 : 427-430

publication ID	https://doi.org/ 10.11646/zootaxa.5051.1.17
publication LSID	lsid:zoobank.org:pub:168B0219-6287-4C93-B37F-0451BDAAB99F
DOI	https://doi.org/10.5281/zenodo.5572718
persistent identifier	https://treatment.plazi.org/id/A5629512-EA36-4481-A075-61A97BF2EA94
taxon LSID	lsid:zoobank.org:act:A5629512-EA36-4481-A075-61A97BF2EA94
treatment provided by	Plazi
scientific name	Stylicletodes wellsi
status	sp. nov.

Treatment

Stylicletodes wellsi sp. nov.

( Figs. 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 )

urn:lsid:zoobank.org:act:A5629512-EA36-4481-A075-61A97BF2EA94

Type locality. East China Sea (29°31.002’N, 122°36.798’E); 25 m depth; silt GoogleMaps .

Type material. Holotype: ♀ dissected on three slides ( MBM189255 View Materials ) . Paratypes: (a) 1 ♀ dissected on five slides ( MBM189256 View Materials ) , 1 ♂ ( MBM189257 View Materials ) on three slides; from type locality; (b) 1 ♂ ( MBM189258 View Materials ) partly dissected on two slides; from East China Sea (29°25.656’N, 122°58.998’E); 61 m depth; fine sand. All type specimens collected on 12 December 2016 GoogleMaps .

Other material. (a) 1 ♀ ( MBM189259 View Materials ); from type locality; collected on 12 December 2016; (b) 1 ♀ ( MBM189261 View Materials ); 29°25.656’N, 122°58.998’E; 61 m depth; fine sand; collected on 12 December 2016; (c) GoogleMaps 1 ♀ ( MBM189260 View Materials ); 28°52.998’N, 122°44.502’E; 66 m depth; silt; collected on 18 December 2016; (d) GoogleMaps 1 ♂ ( MBM189262 View Materials ), 31°40.2’N, 122°30’E; 28 m depth; silt; collected on September 2016; (e) GoogleMaps 1 ♂ ( MBM189263 View Materials ) DH4- 5; 28°38.4’N, 124°37.8’E; 81 m depth; silt; collected on October 2014 GoogleMaps . All specimens collected in the East China Sea and preserved in 75 % ethanol.

Etymology. The species is named in honour of Professor John Berkeley James Wells, in recognition of his massive contributions to our knowledge of harpacticoid taxonomy and systematics.

Description of female. Total body length, measured from anterior margin of rostrum to posterior margin of caudal rami, ranging from 365 to 392 μm (mean = 377 μm; n = 4).

Habitus ( Fig. 1A, B View FIGURE 1 ) slender, curved ventrally in lateral aspect; P1-bearing somite fused to cephalosome forming cephalothorax. Without distinct demarcation between prosome and urosome. Rostrum fused to cephalothorax; triangular, ventrally recurved in lateral aspect, with two sensilla subapically. All somites with dorsal setules along posterior margin except for anal somite. Prosomites with pairs of papillary socles dorsally, each bearing one apical sensillum. Genital double-somite with vestigial P6 represented by two setae (outermost seta longer than innermost) in proximal half of genital somite ( Fig. 1C View FIGURE 1 ); ventral surface relatively smooth, posterior margin with transverse row of strong spinules; genital field with large copulatory pore located near posterior margin. Genital double-somite and second abdominal somite with dorsolateral and ventrolateral papillary socles around posterior margin ( Fig. 1A–C View FIGURE 1 ); ventral surface of second and third abdominal somites with transverse spinule row near posterior margin ( Fig. 1C View FIGURE 1 ). Ventral surface of anal somite partially cleft medially ( Fig. 1C View FIGURE 1 ); anal operculum ( Fig. 1A, C View FIGURE 1 ) produced into long setular extension, flanked by two sensilla. Caudal rami ( Fig. 1B View FIGURE 1 ; note that the rami in Fig. 1A View FIGURE 1 are foreshortened because of the mounting position of the specimen) exceedingly narrow and elongated, about 13 times as long as wide; with one outer proximal seta, distally with three setae, inner margin with one seta near distal fifth of caudal ramus.

Antennule ( Fig. 2A View FIGURE 2 ) five-segmented; surface of all segments smooth; fourth segment shortest; with aesthetasc on third segment; fifth segment with two spiniform setae along anterior margin, four apical setae, and three setae along posterior margin. Armature formula: 1-[1], 2-[4], 3-[3 + (1 + ae)], 4-[1], 5-[9].

Antenna ( Fig. 2B View FIGURE 2 ). Surface of allobasis smooth; with one proximal and one subdistal abexopodal seta. Exopod one-segmented, with two setae, one subdistal and one distal. Free endopodal segment with longitudinal row of inner spinules proximally; some outer spinules subdistally; two outer subdistal spines laterally; one pinnate outer distal spine; one geniculate apical seta and three apical spines; and one inner distal spine.

Labrum ( Fig. 1D View FIGURE 1 ) triangular, with few long spinules around pointed apex.

Mandible ( Fig. 2C View FIGURE 2 ). Gnathobase elongate and narrow; with four teeth. Palp vestigial, represented by two slender setae.

Maxillule ( Fig. 2D View FIGURE 2 ). Arthrite with five naked distal elements around distal margin; coxal endite with two setae; basis with two apical setae.

Maxilla ( Fig. 2E View FIGURE 2 ). Syncoxa unornamented, with two endites, proximal endite with one strong seta; distal endite with one pinnate and two naked setae; allobasis with one strong claw bearing one seta; endopod represented by two slender setae.

Maxilliped ( Fig. 2F View FIGURE 2 ) three-segmented, comprising of unarmed coxa and basis, and one-segmented endopod represented by distal claw.

P1 ( Fig. 3A–B View FIGURE 3 ) slender. Intercoxal sclerite narrow, straight and naked. Coxa without ornamentation. Basis with two strong spinules around base of robust outer basal spine. Exopod three-segmented, all segments without armature along inner margin; first segment slightly shorter than second, each with one spinulose spine and several spinules along outer margin; distal segment about three times as long as second, with two spinulose apical setae, and two spinulose outer spines. Endopod two-segmented; proximal segment short, unarmed; distal segment about 8.4 times as long as proximal, with row of inner spinules subdistally; with one subdistal inner seta and one unipinnate seta apically.

P2 ( Fig. 3C–D View FIGURE 3 ) slender. Intercoxal sclerite unornamented. Coxa almost square, without ornamention. Basis with transverse row of spinules subdistally, with outer spine. Exopod three-segmented, all segments without armature along inner margin; first segment with spinules along distal and outer margins, and one spinulose outer spine; second segment about 1.5 times as long as first, with one spinulose spine and few spinules along outer margin; distal segment about 3.3 times as long as second, with row of spinules along inner margin, two spinulose apical setae and two spinulose outer spines. Endopod two-segmented; proximal segment short, unarmed; distal segment about 16.7 times as long as proximal, with two strong spinules near inner subdistal margin, spinule row along outer margin, and two long, spinulose apical setae.

P3 ( Fig. 4A View FIGURE 4 ) with smooth and wide intercoxal sclerite. Coxa smooth, almost trapezoidal. Basis with transverse row of spinules, with long outer seta (not shown in figure). Exopod three-segmented; first segment with outer and subdistal spinules and one spinulose outer spine; second segment as long as first, with one spinulose inner seta, and one spinulose spine and several spinules along outer margin; distal segment about 2.5 times as long as second, with two spinulose inner setae, two spinulose setae and one spinulose spine apically, and one spinulose outer spine. Endopod two-segmented; proximal segment short, unarmed; distal segment about 12.3 times as long as proximal, with two spinules along inner margin, long row of spinules along outer margin, and two naked apical setae.

P4 ( Fig. 4B View FIGURE 4 ) slender. Intercoxal sclerite smooth and wide. Coxa smooth, slightly broader than long. Basis with row of subdistal spinules and long, sparsely plumose, outer seta. Exopod three-segmented; first segment with few subdistal spinules and one spinulose outer spine; second segment as long as first, with one spinulose inner seta and one spinulose outer spine; distal segment about 2.8 times as long as second, with one spinulose inner seta, two spinulose setae and one spinulose spine apically, and one spinulose spine and several spinules along outer amrgin. Endopod two-segmented; proximal segment short, unarmed; distal segment about 10.7 times as long as proximal, with several inner spinules long inner and outer margins, and one spinulose apical seta.

Armature formulae of P1–P4 as follows:

P5 ( Fig. 7C View FIGURE 7 ). Fifth legs not fused medially. Baseoendopod and exopod not fused, elongate, the former with outer basal seta. Endopodal lobe extending to almost halfway length of exopod; with four naked setae (one inner and three apical), median apical one reduced in length. Exopod long, about 12.5 times as long as greatest width; with three outer, one apical, and one subdistal inner seta; all setae naked.

Description of male. Total body length, measured from anterior margin of rostrum to posterior margin of caudal rami, ranging from 360 to 380 μm (mean = 369 μm; n = 3).

Habitus ( Fig. 5A View FIGURE 5 ) generally as in female, except urosomites 2 and 3 not fused, and pro- and urosomites without setules dorsally; transverse spinular row on first abdominal somite shorter and abdominal spinulation sparser than in female.

Antennule ( Fig. 5C View FIGURE 5 ) chirocer, five-segmented with geniculation between fourth and fifth segments; surface of all segments smooth; with aesthetasc on fourth and fifth segments. First segment with one naked seta; second segment with small plumose seta and five naked setae; third segment shortest; fourth segment swollen; apex of fifth segment recurved. Armature formula: 1-[1], 2-[6], 3-[6], 4-[2 + (1 + ae)], 5-[7 + (1 + ae)].

Antenna, mandible, maxillule, maxilla, maxilliped, and P4 as in female.

P1 ( Fig. 6A View FIGURE 6 ). Intercoxal sclerite narrow, straight and naked. Praecoxa narrow, triangular, without ornamentation. Distal segment of endopod about seven times as long as proximal, with two spinules along inner margin. Otherwise as in female.

P2 ( Fig. 6B View FIGURE 6 ) as in female, except for distal segment of endopod slightly swollen medially, and with more spinules along inner margin.

P3 ( Fig. 7A View FIGURE 7 ) Coxa and basis as in female, except for fewer subdistal spinules on basis. Endopod sexually dimorphic, three-segmented; first segment as in female; second segment longest, with spiniform recurved apophysis arising from inner margin; third segment with two naked apical setae. Exopod three-segmented, first and second segments as in female; third segment with three inner setae, otherwise as in female.

P5 ( Fig. 7B View FIGURE 7 ). Fifth legs not fused medially. Baseoendopod with outer basal seta and vestigial endopodal lobe bearing two naked setae apically and two spinules subdistally along inner margin. Exopod elongate, about 5.8 times as long as greatest width; with one outer, one subdistal inner and two apical setae.

Sixth legs represented by unarmed flaps.